Facebook has been ramping up its efforts to create new revenue streams and one way they are doing this is by offering users more paid services, like its paid messaging system, which is still in testing.

Basically, the service allows users to pay Facebook a fee to send a message directly to the inbox of a person they are not connected with on Facebook. If a user wants to avoid a fee, the message will be sent to the recipient's 'other' folder in their messages.

Facebook launched the trial service last month and originally said that it would charge $1 to route messages to strangers' inbox. It's unclear why the social media giant is now charging some people an increased fee of $100 to direct a message to Zuckerberg's inbox.